Packaging technology for integrated circuit structures has been continuously developed to meet the demand toward miniaturization and mounting reliability. Recently, as the miniaturization and high functionality of electric and electronic products are required, various techniques have been disclosed in the art.
By using a stack of at least two chips, in the case of a memory device for example, it is possible to produce a product having a memory capacity which is twice as large as that obtainable through semiconductor integration processes. Also, a stack package provides advantages not only of an increase in memory capacity but also in regards to mounting density and mounting area utilization efficiency. Due to this fact, research and development of stack package technology has accelerated.
As an example of a stack package, a through-silicon via (TSV) has been disclosed in the art. The stack package using a TSV has a structure in which the TSV is disposed in a chip so that chips are physically and electrically connected with each other through the TSV. Generally, a TSV is formed by etching a vertical via through a substrate and filling the via with a conductive material, such as copper. To increase the transmission speed and for high-density fabrication, the thickness of a semiconductor wafer comprising multiple integrated circuit structures each having the TSV should be reduced efficiently.
However, in order to reduce the thickness of the wafer and form the TSV in the corresponding integrated circuit structure, the deposition of a silicon nitride (SiN) layer on the backside of the wafer and multiple chemical mechanical polishing (CMP) process are required in the prior art process, which is complex and expensive. An example is described in an article entitled “A 3D Stacked Memory Integrated on a Logic Device Using SMAFTI Technology” by Yoichiro Kurita, et al., ECTC 2007 Electronic Components and Technology Conference paper, pages 821 to 829. Therefore, there is a need to provide a novel TSV backside process to reduce manufacturing complexity and cost.